To be sure that I understand, you've tried two power/driver boards, and more than one saucer board, and the symptom persists, right?
if that is the case, then we must look elsewhere...
...flip the MPU-to-Power/Driver board ribbon over (on both ends). Test again.
...Reseat the ASIC. Remove MPU, place on flat hard surface, press firmly on the ASIC, reinstall MPU. Test again. We removed the MPU to avoid flexing the PCB too much.
...try a different MPU. Test again.
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Chris Hibler - CARGPB #31
http://ChrisHiblerPinball.com/Contact ... for board repairs
http://www.PinWiki.com - The Place to go for Pinball Repair Info